Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heparin cofactor II (HCII) inhibits thrombin rapidly in human plasma in the presence of heparin or dermatan sulfate. To determine the minimum structure of dermatan sulfate required to activate HCII, the glycosaminoglycan was partially degraded by sequential treatment with periodate, [3H]borohydride, and sulfuric acid. Labeled oligosaccharide fragments were separated by gel filtration chromatography. Purified fragments were then applied to a column of HCII bound to concanavalin A-Sepharose, and bound oligosaccharides were eluted with a gradient of sodium chloride. Di-, tetra-, and hexasaccharide fragments did not bind to HCII, while 15% of the octasaccharides and up to 45% of larger fragments bound. Octasaccharides that bound to the HCII column had a greater negative charge than the run-through material based on anion-exchange chromatography, suggesting that they contained a greater number of sulfate groups per molecule. Fragments of dermatan sulfate containing a minimum of 12-14 sugar residues accelerated inhibition of thrombin by HCII. Fragments of this length that bound to the column of immobilized HCII had molar specific activities greater than those of the fragments that did not bind. These studies suggest that HCII is activated by dermatan sulfate fragments greater than or equal to 12 residues in length that contain a specific octasaccharide sequence required for binding to the inhibitor.
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PMID:Molecular size of dermatan sulfate oligosaccharides required to bind and activate heparin cofactor II. 375 34

Clinical investigation was carried out into the coagulation and fibrinolytic systems in a series of patients undergoing intraamniotic instillation of dinoprost tromethamine (prostaglandin F2alpha, or PGF2alpha) for 2nd-trimester abortion. 20 healthy women, aged 14-27 years, were studied. The 1st 8 patients received PGF2alpha, 30 mg at hour 0 and 25 mg at hour 6 and again at hour 24 if needed. The last 12 patients received 30 mg at hour 0, and 25 mg at hour 8, 24, and 32 if necessary. The PGF2alpha used did not contain sodium chloride. 18 of the patients aborted in an average of 16 hours and 7 minutes; 2 required additional procedures. Some vomiting and 1 instance of fever but no other significant side effects were noted. Coagulation studies in these patients were normal. The prothrombin time, thrombin time, euglobulin lysis time, and plasminogen levels were normal and unchanged from the control blood value. Plasma fibrinogen concentration increased slightly 6 hours after the initial infusion of PGF2alpha. Red blood cell fragmentation was not observed at any time during labor, delivery, or the postpartum period. The increased white blood count was statistically significant but without clinical significance. Previous studies have shown that use of saline solution to achieve abortion causes alterations in the coagulation and fibrinolytic systems. This study with PGF2alpha showed no such effects.
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PMID:Abortion and coagulation by prostaglandin. Intra-amniotic dinoprost tromethamine effect on the coagulation and fibrinolytic systems. 474 Jun 10

The thrombin clotting time and the fibrin polymerization test were performed in 64 patients with liver cirrhosis. Each test was made with thrombin diluted with 150 mmol/l sodium chloride and 25 mmol/l calcium chloride. The thrombin-in-NaCl clotting time was found to be prolonged in 39% of cirrhotic patients, whereas fibrin polymerization was defective in 65% of them. Dilution of thrombin with calcium chloride diminished the number of abnormal results of both tests in patients with liver cirrhosis. Among the performed tests most sensitive test proved to be the polymerization of fibrin induced by thrombin diluted with sodium chloride.
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PMID:Thrombin clotting time and fibrin polymerization in liver cirrhosis. 760 83

Factor XIII A-chain-fibrin interactions regulate factor XIIIa formation and fibrin cross-linking. A microtiter plate assay was developed for studying these interactions. Microtiter plate wells were coated with fibrinogen and converted to fibrin by thrombin. After blocking the wells with bovine serum albumin, factor XIII A-chain was added and binding was monitored by incubating first with anti-factor XIII followed by anti-rabbit IgG-alkaline phosphatase. Enzymatic hydrolysis of p-nitrophenyl phosphate was quantitated by the absorbance at 405 nm. BInding was specific, sensitive, rapid, saturable, and reversible, requiring only nanograms of either factor XIII or fibrin. Binding was time- and concentration-dependent and independent of divalent cations. The bound material was identified as factor XIII A-chain by sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting. Factor XIII binding was inhibited > 75% by 250 mM sodium chloride or 250 nM anti-factor XIII IgG. The method was also suitable for demonstrating binding using 0.8% plasma or with r-factor XIII expressed in Saccharomyces cerevisiae or Escherichia coli. This method is suitable for identifying the binding sites that are important for plasma factor XIII activation and factor XIIIa activity.
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PMID:A microtiter plate assay for factor XIII A-chain-fibrin interactions. 805 54

Diabetic vascular disease is associated with a state of hypercoagulability and altered endothelial properties, leading to elevated plasma levels of endothelium-derived peptides and proteins, e.g. endothelin-1, von Willebrand factor or fibronectin. This study determined dynamic immunoreactive endothelin-1 secretion by human umbilical vein endothelial cells exposed to thrombin (5 x 10(6) mU/l) in the presence (40 mmol/l) and absence (5.5 mmol/l) of excessive glucose in the cell culture medium. Exposure to high glucose and thrombin concentrations was initiated after cell confluency and applied for 24 h for measurements of endothelin-1 and for 2 and 5 h for the determination of preproendothelin-1, von Willebrand factor and fibronectin messenger ribonucleic acid. Comparisons were made versus cells incubated with normal glucose concentrations or with high mannose or NaCl concentrations as osmotic control. Neither preproendothelin-1, fibronectin and von Willebrand factor messenger ribonucleic acid expression nor endothelin-1 release was affected by high concentrations of glucose, mannose or sodium chloride.
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PMID:Stimulation of endothelin-1 production by thrombin, but lack of interference by high ambient glucose in vitro. 815 1

In the living organism, capillary growth frequently occurs in a fibrin-rich extracellular matrix. The structure and the mechanical properties of fibrin clots are influenced by various macromolecules (i.e., hyaluronic acid and thrombospondin) and also by pH, ionic strength, and thrombin concentrations of the milieu in which they polymerize. The configuration (three-dimensional architecture) and the rigidity of fibrin clots correlate with their opacity measured by spectrophotometric absorbance readings at 350 nm. By using bovine pulmonary artery endothelial cells and bovine fibrinogen, we show here that transparent fibrin clots (A(350) < 1.0), polymerized at > or = pH 7.5 or in the presence of increased thrombin or sodium chloride concentrations, strongly stimulated capillary morphogenesis in vitro. In contrast, opaque fibrin gels (A(350) > 1.5), polymerized at pH 7.2 or in the presence of dextran, stimulated only the migration of endothelial cells but not capillary morphogenesis. We demonstrate that the angiomorphogenic effects of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are strongly dependent on the structure of the fibrin clots. Our findings suggest that bFGF/VEGF primarily stimulate the proliferation of endothelial cells, whereas the three-dimensional architecture of the fibrin matrix is decisive for capillary morphogenesis.
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PMID:The configuration of fibrin clots determines capillary morphogenesis and endothelial cell migration. 899 33

Factor Xa is a serine protease positioned at the convergence point of the intrinsic and extrinsic coagulation pathways and is therefore an attractive target in the development of novel anticoagulant drugs. The objective of this study was to evaluate the efficacy of CI-1031 (N-[2-[5-amidino-2-hydroxyphenoxy]-6-[3-(1-methyl-1H-imidazolin-2-yl)-phenoxy]-3,5-difluoropyrid), a potent and selective inhibitor of Factor Xa, in a canine electrolytic injury model of arterial and venous thrombosis. Enoxaparin (enoxaparin sodium), a low molecular weight heparin currently approved for treatment and prevention of deep vein thrombosis and unstable angina, was also tested for efficacy in this model. CI-1031 was administered intravenously to anesthetized dogs at three doses: 1.25, 2.5 and 5 microg/kg/min (n=5 for each group) as a continuous infusion for 5.5 h. The control group (n=5) received a continuous infusion of vehicle (3.69 mmol citric acid and 0.9% sodium chloride solution) at a rate of 1 ml/kg/h. Ninety minutes after administration of CI-1031 prothrombin times increased 1.2-, 1.6- and 2.0-fold over baseline values in the 1.25, 2.5 and 5 microg/kg/min groups, respectively. The time to formation of an occlusive thrombus in the femoral arteries averaged 69+/-5 min in the control group compared to 127+/-19, 192+/-33 and 219+/-15 min in the low-, mid- and high-dose CI-1031 groups. In the femoral veins, occlusion time in the controls averaged 56+/-11 min compared to 153+/-22, 137+/-30 and 214+/-26 min in the three treatment groups. Thrombus weights in the control arteries averaged 51+/-4 mg compared to 45+/-5, 28+/-10 and 15+/-3 mg in the CI-1031 treated groups. On the venous side, control thrombus weights averaged 96+/-18 mg compared to 75+/-16, 51+/-16 and 25+/-4 mg in the low-, mid- and high-dose CI-1031 groups. A plasma CI-1031 concentration of approximately 400 ng/ml was associated with a 50% reduction in thrombus weight relative to control animals. Enoxaparin was administered intravenously at a loading dose of 50, 100 or 200 IU/kg for 1 h followed by a maintenance infusion of 25, 50 or 100 IU/kg/h for 4.5 h. The most dramatic changes in coagulation parameters were observed in thrombin time with virtually no changes in prothrombin time. Enoxaparin elicited a dose-dependent increase in time to thrombotic occlusion and a dose-dependent decrease in thrombus weight similar to that observed with CI-1031. Time to occlusion in the enoxaparin-treated groups averaged 117+/-33, 188+/-32 and 217+/-22 min in the low-, mid- and high-dose groups in the femoral arteries and 84+/-22, 171+/-31 and 133+/-33 min in the femoral veins. Thrombus weights averaged 33+/-10, 12+/-5 and 10+/-4 mg in the arteries and 32+/-9, 13+/-2 and 21+/-6 mg in the veins in the low-, mid- and high-dose groups. Blood loss with CI-1031 tended to be less than enoxaparin at doses that provided comparable efficacy. These results demonstrate that CI-1031, like enoxaparin, is an effective antithrombotic agent in an established canine model of arterial and venous thrombosis. CI-1031 provided dose-dependent efficacy with minimal changes in ex vivo coagulation parameters, suggesting it may be a safe and effective antithrombotic agent for both arterial and venous indications.
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PMID:The antithrombotic effects of CI-1031 (ZK-807834) and enoxaparin in a canine electrolytic injury model of arterial and venous thrombosis. 1174 Sep 55

The major active form of human thrombin, alpha-thrombin, was analyzed by hydrophobic interaction high-performance liquid chromatography (HIC-HPLC). The chromatographic system included a polymeric phenyl column and elution was performed by a gradient, 2-0M sodium chloride (5-20 min). Total analysis time was 30 min per injection. By this method, a good resolution between alpha-thrombin and the proteolytically modified thrombin forms, beta- and gamma-thrombin, was obtained. In addition, the thrombin preforms, prothrombin, prethrombin 1, and prethrombin 2, were also resolved from alpha-thrombin in the system. The results from the HIC method were compared to those obtained from non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. By this high-resolution chromatographic method, the rapid analysis of purified alpha-thrombin is possible.
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PMID:Analysis of human alpha-thrombin by hydrophobic interaction high-performance liquid chromatography. 1251

The gene coding for APG8a (At4g21980), a protein from Arabidopsis thaliana, is involved in the autophagy process. The protein is an interesting candidate for structure determination by NMR spectroscopy. Toward this end, APG8a fused to an N-terminal His-tag has been expressed in Escherichia coli under a T7 expression system, refolded in vitro, and kept soluble by slight destabilization. The expressed protein appeared in both the soluble and the insoluble fractions. The whole-cell lysate was denatured by the addition of guanidinium chloride. The protein was immobilized on nickel-agarose resin and refolded by stepwise decrement of the denaturant. The elution buffer was 20 mM sodium phosphate, pH 7.0, with 1% glycerol, 0.5 M urea, 300 mM NaCl, and 1 M imidazole. After the removal of imidazole by ultrafiltration, the His-tag was cleaved with biotinylated thrombin. The protein product was kept in 20 mM sodium phosphate, pH 7.0, with 1% glycerol, 0.5 M urea, and 300 mM NaCl. The protein was found to aggregate extensively over time if any one of the three ingredients (sodium chloride, urea, or glycerol) was omitted. The yield of the protein was around 20 mg/L Luria-Bertani culture medium. The (1)H-(15)N NMR correlation spectrum of (15)N-labeled APG8a showed the characteristic signature of a folded protein; thus, the solutes appear to have no deleterious effect on the sample. These solution conditions kept the protein soluble and unaggregated for at least 2 days (enough time for NMR data collection). This approach of balanced stabilization-destabilization may offer a general approach for structural investigations of proteins that tend to aggregate.
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PMID:Prevention of aggregation after refolding by balanced stabilization-destabilization: production of the Arabidopsis thaliana protein APG8a (At4g21980) for NMR structure determination. 1500 62

Femoral artery pseudoaneurysm is a common complication associated with cardiac catheterization procedures. Ultrasound-based techniques (e.g., mechanical compression, thrombin injection) and open surgical intervention are frequently used in the management of pseudoaneurysm. The investigators report their prospective experience with a novel method for the treatment of pseudoaneurysm after cardiac catheterization using ultrasound-guided, para-aneurysmal injection of physiologic saline. Sixty-four consecutive patients with pseudoaneurysms after cardiac catheterization were treated using normal saline (0.9% sodium chloride 25 to 60 ml) injected into the tissue surrounding the tract connecting the pseudoaneurysm with the femoral artery, followed by manual pressure of short duration. In none of the patients was concomitant antithrombotic therapy (aspirin [n = 63], clopidogrel [n = 45], unfractionated or low-molecular-weight heparin [n = 23], and warfarin [n = 5]) discontinued during the closure attempt. Fifty-nine of the 64 pseudoaneurysms (92%) were successfully occluded using saline injection. In 5 patients in whom saline injection failed, the pseudoaneurysms were successfully treated with thrombin injection (n = 4) or ultrasound-guided compression (n = 1). In all 64 patients, pseudoaneurysm closure was confirmed by ultrasound at 24 hours. The procedure was very well tolerated by the patients, and no side effects or complications were noted. In conclusion, ultrasound-guided saline injection affords a simple, safe, and effective alternative treatment for the closure of postcatheterization pseudoaneurysms.
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PMID:Treatment of post-catheterization femoral artery pseudo-aneurysm with para-aneurysmal saline injection. 1847 52


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